RFID transponder chip with a programmable wake-up

Abstract

An RFID transponder chip includes at least one antenna to pick-up and transmit radio-frequency signals, a rectifier to store charge on at least one capacitor at a rectified voltage from the picked-up radio-frequency signals, a power-on reset circuit to maintain a logic unit in a reset state if the rectified voltage level is less than a power-on reset or wake-up voltage of the power-on reset circuit for operating the logic unit. The RFID transponder chip further includes a non-volatile memory, in which are stored one or several trim values. Said non-volatile memory is directly connected to the power-on reset circuit to be able to provide at least one trim value to trim the power-on reset circuit at a rectified voltage level below a wake-up voltage level.

Description

FIELD OF THE INVENTION[0001]The present invention relates to an RFID transponder chip with a programmable wake-up. Said RFID transponder chip includes in particular an antenna to pick-up radio-frequency signals, a rectifier to store charge on capacitors at a rectified voltage from the picked-up radio-frequency signals, and a power-on reset circuit to maintain a logic unit in a reset state if the rectified voltage level is less than a power-on reset or wake-up voltage of the power-on reset circuit from which the logic unit can operate.BACKGROUND OF THE INVENTION[0002]In order to wake-up a conventional passive RFID transponder chip, the rectified voltage from an RF signal picked-up by the antenna of the chip has to be greater than a power-on reset voltage previously set. When the rectified voltage across capacitors is sufficient from an RF signal picked-up by the antenna, the chip circuit is powered to communicate with a reader. Usually some power-on reset trim values can be stored in...

AI Technical Summary

Benefits of technology

The solution enhances the transponder chip's sensitivity for initial communication, allowing it to operate at lower voltages and maintain communication at greater distances from the reader, with reduced variability in power-on reset voltage levels, leading to improved performance and manufacturing yield.

Problems solved by technology

However, the non-volatile memory stays disabled as do several electronic parts of the chip, and cannot be read, if the rectified voltage is under the level of an untrimmed power-on reset voltage.

So the chip sensitivity of a conventional passive RFID transponder chip is poor, which is a drawback.

In practice, it means that for the first communication the transponder chip must be brought close to the reader to awaken before it can be moved further away while staying awake, which is a drawback.

So in this case, it is necessary to wait for wake-up of the transponder chip before eventually tuning the power-on reset circuit with trim data values stored in said EEPROM memory, which is a drawback.

The concept in U.S. Pat. No. 6,980,084 does not trim the power-on reset release voltage for a rising power supply level, rather it trims the falling power-on reset assert voltage by mode (passive or active) and not even by chip, which is a drawback.

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